Judges ruled that banning the fleeting use of expletives ran contrary to the First Amendment of the US Constitution which protects free speech.

They also said the tough indecency policy pursued by the broadcast regulator, the Federal Communications Commission, was "unconstitutionally vague" and could have the "chilling effect" of promoting wide self-censorship by broadcasters.

The ruling means an end to regulations which have exposed broadcasters to potentially huge fines for incidents such as Janet Jackson's wardrobe malfunction and celebrities swearing at awards ceremonies